1. Field of the Invention
The present invention relates to a method of distributing stream data and system thereof, and more particularly to a flexible method of distributing stream data which copes with the increase and decrease of servers and receivers.
2. Background Art
Streaming distribution services allowing a wide range of users to view stream data generated in real time are attracting great attention. A typical example of conventional streaming distribution is shown in FIG. 1. A server 130 receives stream data 120 outputted from a streaming source 110 and transmits the data to each receiver 140 being a user. However, there has hitherto been no appropriate technique of improving reliability and availability in such streaming distribution. Meanwhile, in the field of data distribution which handles data whose transmission size is preliminarily known, as a technique of making a server redundant each server distributes divided data in order to improve reliability. This technique has been known and disclosed in Published Unexamined Patent Application No. 2004-70712, and so on. This method, which presupposes that each distribution server holds the same distribution data, is not easily applicable to variable-size stream data generated in real time. Moreover, the distribution may be interrupted due to a reconnection to a reserved server upon a trouble during a streaming distribution. Furthermore, in the addition of a reserved server, such processing as pre-providing a server list to a reproduction side are needed, thus making it difficult to change flexibly the server configuration.
To solve the above described technical problems, the objectives of the present invention are as follows:                To provide a method and system which improves reliability and availability in general services for performing variable-size streaming distributions;        To provide a method and system which distributes data to receivers without interrupting the streaming service upon a trouble of server;        To provide a method and system for streaming distribution which flexibly copes with the increase and decrease of receivers;        To provide a method and system which, in using servers for streaming distribution redundant, does not create an extra load on a particular server;        To provide a method and system which, in using redundant servers for streaming distribution, eliminates flexibly a troubled server without affecting the streaming being distributed; and        To provide a method and system which, in using redundant servers redundant for streaming distribution, easily adds a new server without affecting the streaming being distributed.        